(1) Field of the Invention
The present invention relates to a high-speed bevel gear transmission system for transmitting power between input and output shafts the axes of which intersect each other.
(2) Description of the Prior Art
In order to transmit power between two shafts the axes of which intersect each other, a bevel gear transmission system can be generally used. The bevel gear transmission system, however, has two problems as follows in connection with its characteristics.
One of these problems is that the dimensions of producible bevel gears are considerably smaller than those of spur gears since the facility for manufacturing bevel gears is limited in scale. Namely, the problem is that the dimensions of producible bevel gears are limited. This means that the magnitude of power which can be transmitted by bevel gears is also limited. In other words, it cannot be expected to obtain bevel gears which permit the transmission of a large degree of power.
The other problem is that a bevel gear transmission system produces a large thrust load in the axial direction. In general, thrust bearings for supporting a thrust load, which have a large load capacity, are only permitted a low rate of revolution, and on the other hand, thrust bearings used for the same purpose, which have a large allowable rate of revolution, are small in load capacity.
Accordingly, it is desirable to use angular contact ball bearings having a large allowable rate of revolution for transmitting power at high speed. However, the life of ball bearings of this type is limited due to their small load capacity. It is, in fact, a very difficult technical problem to transmit power at high speed (effect the transmission of a high horsepower) with a bevel gear transmission system of this kind while maintaining a long life.